1. Field of Invention
The present invention relates to a door switch device having a rubber cap for waterproofing which is fitted over a distal end portion of a moving member.
2. Related Art
A door switch device (courtesy lamp switch) for turning on and off, for example, an interior roof lamp as the door of an automobile is opened or closed is arranged such that, as its parts are shown in FIGS. 4 to 6, a moving member 2 made of a hard plastic is provided in a body case 1 having a substantially hollow cylindrical shape and provided with a flange portion 1a in its front portion, in such a manner as to be movable in the projecting or retracting direction (in the left-and-right direction in the drawings) so as to be passed through an opening 1b thereof. A rubber cap 3 for waterproofing having the shape of a hollow cylindrical cap is attached to a front portion of the flange portion 1a so as to be fitted over a distal end portion of the moving member 2.
In this case, the moving member 2 is urged in the projecting direction by a spring in the body case 1, and when a door 4 is opened, the moving member 2 is located at the projecting position shown in FIG. 4, whereas when the door 4 is closed, the moving member 2 is pressed together with the rubber cap 3 by the door 4 and is displaced to the retracted position, as shown in FIG. 5. As a result, a contact mechanism in the body case 1 is operated by the displacement of the moving member 2 between its projecting position and retracted position in correspondence with the opening or closing of the door 4. It should be noted that the rubber cap 3 is shaped in the form of a so-called bellows having a crest and a trough arranged in the axial direction, and the crest portion (large-diameter portion) in the middle is formed as a fold. As the folded portion undergoes expansion and contraction, the rubber cap 3 can be easily deformed resiliently in the projecting or retracting direction of the moving member 2.
The door 4 has vertical free play, though slight, with respect to the body of the automobile, and there are cases where the door 4 vibrates vertically with the door 4 closed during the traveling of the automobile, or becomes slightly offset vertically when the door 4 is opened or closed. However, with the conventional door switch device, there are cases where, owing to the vertical free play or vibration of the door 4, the rubber cap 3 with its distal end surface held in close contact with the door 4 becomes offset vertically by following up the vertical free play or vibration, and undergoes deformation such as to be distorted vertically with the fold bent, as shown in FIG. 6.
When the rubber cap 3 thus undergoes the vertical displacement, the distal end surface of the moving member 2 in the vertically displaced state adheres to the rear surface of the distal end portion of the rubber cap 3. Hence, there have been drawbacks in that even if the door 4 is opened, the rubber cap 3 is difficult to return to its original shape, that the smooth operation of the moving member 2 is possibly hampered, and that breakage can occur in the rubber cap 3 at its portion of contact with the moving member 2.
The invention has been devised in view of the above-described circumstances, and its object is to provide a door switch device in which a rubber cap for waterproofing is fitted over a distal end portion of a moving member, and which is capable of effectively preventing the drawbacks ascribable to the displacement of the rubber cap in a direction different to the projecting or retracting direction of the moving member.
According to the present invention, there is provided a door switch device having on a front portion of a body case a moving member adapted to project or retract by the opening or closing of a door so as to operate a contact mechanism as well as a rubber cap for waterproofing which is fitted over a distal end portion of the moving member, provided in that a contact surface of the rubber cap for contact with the door is formed as a low-friction surface having small friction resistance.
According to this arrangement, when the door is closed, the moving member is pressed by the door through the rubber cap and moves in the retracting direction. In this closed state of the door, however, there are cases where the door vibrates or becomes offset, for instance, in the vertical direction with the rubber cap held in close contact with the door. Nevertheless, since the contact surface of the rubber cap for contact with the door is formed as a low-friction surface having small frictional resistance, and the rubber cap is liable to slip on the door, the displacement of the rubber cap accompanying the vibration or offset of the door is unlikely to occur. Accordingly, it is possible to prevent the drawbacks such as that the rubber cap becomes displaced and fails to return to its original shape.
In addition, the door switch according to the present invention is provided a door switch device having on a front portion of a body case a moving member adapted to project or retract by the opening or closing of a door so as to operate a contact mechanism as well as a rubber cap for waterproofing which is fitted over a distal end portion of the moving member, provided in that contact surfaces of the rubber cap and a distal end portion of the moving member are formed as low-friction surfaces having small friction resistance.
According to this arrangement, since the contact surfaces of the rubber cap and a distal end portion of the moving member are formed as low-friction surfaces having small friction resistance, it is possible to prevent the distal end surface of the moving member from adhering to the reverse surface of the rubber cap. In consequence, even when the rubber cap has become vertically displaced due to the vibration or offset of the door when it is closed, the moving member is able to move smoothly in the projecting direction when the door is opened. Accordingly, it is possible to prevent the drawbacks such as that the displacement of the rubber cap hampers the smooth operation of the moving member.